The present invention relates to an improved currency validator and an improved method of making such a validator. More particularly, it relates to a currency validator which has been designed so that it is adaptable for assembly as either an up-stacker, a down-stacker or a stacker-less unit with only minor modifications.
Currency validator-stacker configurations presently exist which are known as up-stacker or down-stacker units, dependent on how the unit fits into a vending machine. Examples of validator up-stacker units are shown in U.S. Pat. Nos. 4,722,519, 4,765,607, and 4,775,824, all assigned to the assignee of the present application.
It is also known to use magnetic sensors in currency validators to validate and denominate banknotes. See, for example, U.S. Pat. No. 4,628,194, assigned to the assignee of the present application, which discloses a method and apparatus for improved currency validation. In the validator of that patent, a magnetic sensor is disclosed as preferably located above the passageway along which banknotes are transported through the validator. As a result, banknotes such as U.S. banknotes must be inserted portrait side up. Due to the positioning of currency sensors in various prior art units that require currency or banknote insertion portrait side up, prior art down-stacker configurations have typically required a validator of different design for connection to the stacker than the validator used for an up-stacker.
Further, a banknote must typically pass very close to or contact a magnetic sensor for accurate data to be gathered. In the prior art unit of U.S. Pat. No. 4,628,194 or other prior art units, if the magnetic sensor is not properly seated in its housing sensing errors can occur. Further, some prior art arrangements designed to bias a banknote towards the magnetic sensor employed too much pressure, resulting in jamming of the bill in the passageway.
Finally, the accurate determination of bill position in the validator passageway was another problem encountered by some currency validators. Integrated motor and encoder assemblies were used to monitor the motor in order to track the progress of a bill or banknote as it travelled through the validator. This arrangement led to bill positioning errors because of the backlash that occurred in the gearing of the motor drive train when the motor was braked. The backlash caused the bill to move slightly further in the passageway after the motor stopped, a phenomenon not monitored by the integrated motor and encoder assembly. As the validator aged, this backlash problem increased, resulting in the incorrect validation of some banknotes and other problems.